Linear motor armature and linear motor

ABSTRACT

Connectors ( 25   a ), ( 25   b ), ( 25   c ), ( 25   d ), ( 25   e ), and ( 25   f ) for electrically connecting lead wires of armature windings ( 4 ) coiled around armature blocks ( 10 ), ( 11 ), and ( 12 ) are provided at respective ends of a plurality of the armature blocks ( 10 ), ( 11 ), and ( 12 ) such that connections of the armature windings ( 4 ) in the respective armature blocks become parallel connections. The connector pair including the connectors ( 25   b ), ( 25   c ) and the connector pair including the connectors ( 25   d ), ( 25   e ), which are provided between the armature blocks, are embodied as in-phase connections. On condition that the number of phases of the armature winding is taken as three and a magnetic pole pitch of a magnetic field is taken as τp, the armature blocks are spaced apart from each other at intervals of ⅔ τp. As a result, there can be obtained an armature of a linear motor and a linear motor, which can facilitate processing of lead wires of the armature windings and make the operation for assembling the armature blocks efficient and which enable an attempt to increase the thrust of the motor in accordance with an increase in the stroke of the movable element.

TECHNICAL FIELD

The present invention relates to an armature of a linear motor and to alinear motor, which enable an attempt to increase thrust when the lengthof an armature is increased in accordance with an increase in the strokeof a movable member and realize cost reduction and improved efficiencyat the time of assembly of an armature block.

BACKGROUND ART

Conventionally, a linear motor utilized for a machine tool or precisionfeeding of a semiconductor manufacturing system or the like has astructure such as that shown in FIG. 4.

FIG. 4 is a front cross-sectional view showing the entire configurationof a common linear motor, which will be described by means of taking asan example a linear motor having a through-flux-type structure.Reference numeral 1 designates a linear motor; 2 designates an armaturewhich permits penetration of a magnetic flux; 3 designates an armaturecore formed by stacking flat rolled magnetic steel sheets and strips oneon top of the other; 4 designates an armature winding coiled around thearmature core 3; and 5 designates smoothing magnetic field magnets whichare disposed on both longitudinal sides of the armature core 3 so as tooppose each other at right angles by way of a gap and which are formedfrom permanent magnets. Reference numeral 6 designates smoothing yokeswhich have the magnets 5 affixed thereon and permit penetration of amagnetic field; 7 designates a table disposed on an upper surface of thearmature 2; 8 designates linear guides; 8 a designates guide rails; 8 bdesignates sliders; 9 designates an armature mount plate; 9 a designatesfemale screw sections; 22, 23 designate fastening bolts; and 24designates a fixed bed.

In such a linear motor 1, the magnetic-field-side smoothing yokes 6 arefixed on the fixed bed 24, and the armatures 2 are fastened by means ofscrewing the fastening bolts 22 into the female screw sections 9 a ofthe armature mount plate 9 by way of through holes 3 a of the armaturecore 3. The table 7 is fastened by means of screwing the fastening bolts23 into female screw sections 9 b formed in the armature mount plate 9,by way of through holes 7 a. The linear motor 1 is further supported bythe linear guides 8 which are each formed from the guide rail 8 a andthe slider 8 b. The armature 2 carrying the table 7 generates thrust inthe direction of a line of the permanent magnets 5, thereby enablingsmooth linear movement.

Particularly, in relation to the structure of the armature which isrequired to increase the stroke of the movable member according to anapplication, an armature shown in FIGS. 5 and 6 is put forward as thearmature of such a linear motor (described in, e.g., JP-A-2000-278929).

FIG. 5 shows the armature of the linear motor showing a firstbackground-art technique, wherein FIG. 5A is a side cross-sectional viewof the armature, and FIG. 5B is a plan view of the armature when viewedfrom the bottom thereof. The drawings show an example wherein the numberof armature blocks is three and the number of teeth per armature blockis nine.

The armature core 3 includes a first armature block 10, a secondarmature block 11, and a third armature block 12, and spacers 14 areprovided between the armature blocks, thereby maintaining gaps. Thearmature blocks 10 to 12 and the spacers 14 are arranged in thedirection of thrust of the linear motor and fixed by the armature mountplate 9. Each of block cores 31 constituting the respective armatureblocks 10 to 12 has teeth sections 31 a arranged at equal pitches andare sequentially coupled together by way of engagement sections 31 b.

During coil wire processing of the armature 2, an armature winding 4formed from an U-phase coil, a V-phase coil, and a W-phase coil ishoused in each of the teeth 31 a of the respective armature blocks 10 to12 such that a lead wire 13 of each armature winding 4 is led from thebottom of the armature block 31 to the direction of thrust of the linearmotor. Moreover, the surroundings of the armature block and the bottomof the same where the lead wire 13 is provided are fixed with resin mold17. Reference numeral 18 designates a terminal box; and 18 a designatesa connector terminal. The lead wires 13 of the respective armaturewindings are bundled into the terminal box 18 and connected to theconnector terminal 18 a.

The coil wire processing of the other coils of the armature 2 isperformed as shown in FIG. 6. FIG. 6 shows an armature of a linear motorshowing a second background-art technique, wherein FIG. 6A is a sidecross-sectional view of the armature, and FIG. 6B is a plan view of thearmature when viewed from the bottom. The drawings show an examplewherein the number of armature blocks is three and the number of teethper armature block is nine.

In FIG. 6, reference numeral 15 designates a first lead wire throughpassage; and 20 designates a second lead wire through passage. Formed ineach of the spacers 14 provided between the armature blocks 10 to 12 isthe first lead wire through passage 15 having a bore section oriented inthe longitudinal direction (i.e., the direction at right angles to thearmature mount plate 9) of the spacer. The second lead wire throughpassage 20 is formed so as to communicate with the first lead wirethrough passage 15 in the longitudinal direction of the armature mountplate 9. A trench having a depth which enables accommodation of the leadwire 13 is formed in the second lead wire through passage 20 from thesurface of the armature mount plate 9 toward the inside thereof.

However, the background-art techniques have the following problems.

-   (1) During the lead wire processing of the armature winging 4 shown    in FIG. 4, the lead wire 13 of each armature winding 4 is led from    the bottom sections of the armature blocks 10 to 12 to the direction    of thrust of the linear motor, and the lead wires are collectively    extracted to the terminal box. Since the number of block cores 31    and the number of armature blocks are increased, the lead wires 13    of respective phase coils in the bottom sections of the armature    blocks become larger in number and bulky, which is responsible for    deterioration of the efficiency of operation for assembling the    armature block.-   (2) During the lead wire processing of the armature coil 4 shown in    FIG. 5, the volume of lead wires is reduced by effective utilization    of the spacers 14. However, the lead wires are mounted, in a    spreading manner, at a plurality of locations, such as the spacers,    the armature mount plates, and the bottom sections of the armature    blocks. Hence, this configuration also encounters difficulty in    rendering efficient the operation for assembling the armature block.-   (3) Moreover, when the related-art techniques are applied to a case    where the present invention is applied to a plurality of feed rods,    as an example to which the linear motor is applied, the respective    feed rods require a plurality of linear motors having different    thrust specifications. The respective motors require armatures of    different shapes and dimensions. Therefore, this case is    disadvantageous in terms of (1) an increase in costs incurred in    development and investment of the linear motors used in one machine    tool and (2) a necessity for replacing the entire armature block    including armatures with a new armature block when imperfections    have arisen in a part of the armature block.

The present invention is conceived to solve the foregoing problems andis aimed at providing an armature of a linear motor and a linear motor,which facilitate lead wire processing of armature windings, renderefficient an operation for assembling an armature block, and enable anattempt to increase the thrust of a motor in accordance with an increasein the stroke of a movable member.

DISCLOSURE OF THE INVENTION

To solve the problem, the present invention provides an armature of alinear motor having a modular-type armature which is divided into aplurality of armature blocks and around which an armature winding iscoiled, a plurality of the armature blocks being formed by sequentiallycoupling a plurality of block cores, and connectors to be used forelectrically connecting lead wires of armature windings coiled aroundthe armature blocks are provided on both ends of a plurality of thearmature blocks such that connections of the respective armature blocksand connections of the armature windings become serial or parallel,wherein the connectors provided between the armature blocks are in theform of in-phase connections.

Specifically when the number of the armature windings is three and amagnetic pole pitch of a magnetic field is taken as τp, the armatureblocks are separated from each other at intervals corresponding to anelectrical angle of an integral multiple determined by dividing themagnetic pole pitch by the number of sub-divisions of the armatureblocks.

More specifically the armature blocks are separated from each other atintervals of ⅔ the magnetic pole pitch.

More specifically the armature blocks are separated from each other atintervals of 4/3 the magnetic pole pitch.

In a specific enhancement the armature has an armature mount plate whichis arranged in the direction of thrust of the linear motor and providesa retaining function provided on each of the armature blocks, anengagement projection provided at one end of each armature mount plate,wherein an engagement groove is formed in the other end of the same tocouple together the armature blocks.

In yet an other specific enhancement, the armature has a magnetic fielddisposed so as to oppose the armature by way of a gap, wherein themagnetic field is generated by a yoke, and a plurality of permanentmagnets disposed on the yoke such that different polarities are arrangedalternately, and either the armature or the magnetic field is taken as amovable element which moves, and the other is taken as a stator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of linear motor which shows a first embodiment ofthe invention and describes connection of an armature block andconnection of armature windings.

FIG. 2 is a plan view of a linear motor which shows a second embodimentof the invention and describes connection of an armature block andconnection of armature windings.

FIG. 3 shows a linear motor shows a third embodiment of the presentinvention, wherein FIG. 3A is a perspective view of the entire armature,and FIG. 3B is a plan view for describing connection of the armatureblocks.

FIG. 4 is a front cross-sectional view showing the entire configurationof a common linear motor.

FIG. 5 shows an armature of a linear motor of a first related-arttechnique, wherein FIG. 5A is a side cross-sectional view of thearmature, and FIG. 5B is a plan view of the armature when viewed fromthe bottom.

FIG. 6 shows an armature of a linear motor of a second related-arttechnique, wherein FIG. 6A is a side cross-sectional view of thearmature, and FIG. 6B is a plan view of the armature when viewed fromthe bottom.

Reference numerals shown in FIG. 1 designate the following elements:namely, reference numeral 4 designates an armature winding; 5 designatesa permanent magnet; 6 designates a yoke; 10 designates a first armatureblock; 11 designates a second armature block; 12 designates a thirdarmature block; 25 a, 25 b, 25 c, 25 d, 25 e, and 25 f designateconnectors; and 26 designates a neutral point.

BEST MODES FOR IMPLEMENTING THE INVENTION

The present invention will be described hereinbelow on the basis ofillustrated embodiments.

FIRST EMBODIMENT

FIG. 1 is a plan view of linear motor which shows a first embodiment ofthe invention and describes connection of an armature block andconnection of armature windings. The linear motor is identical with therelated-art linear motor in that the linear motor has modular-typearmatures which are divided into a plurality of armature blocks aroundwhich armature windings are wound; and in that each of the armatureblocks is formed by sequentially connecting a plurality of the blockcores. Those constituent elements which are the same as those of therelated-art linear motor are assigned the same reference numerals, andtheir repeated explanations are omitted. Explanations are given of onlythe differences.

In the drawings, reference numerals 25 a, 25 b, 25 c, 25 d, 25 e, and 25f designate connectors, and reference numeral 26 designates a neutralpoint.

The present invention differs from the related art in the followingpoints:

Namely, the connectors 25 a, 25 b, 25 c, 25 d, 25 e, and 25 f forelectrically connecting lead wires of the armature windings 4 coiledaround the armature blocks 10, 11, and 12 are provided at respectiveends of a plurality of the armature blocks 10, 11, and 12 such thatconnections of the armature windings 4 in the respective armature blocksbecome parallel connections. The connector pair including the connectors25 b, 25 c and the connector pair including the connectors 25 d, 25 e,which are provided between the armature blocks, are embodied as in-phaseconnections.

Specifically, in FIG. 1, on condition that the number of phases of thearmature winding is taken as three and that a magnetic pole pitch of amagnetic field is taken as τp, the armature blocks 10, 11, and 12 arespaced apart from each other at intervals corresponding to electricalangles which are integral multiples determined by dividing the magneticpole pitch τp by the number of sub-divisions of the armature blocks.Specifically, the embodiment shown in FIG. 1 is a case where thearmature blocks 10, 11, and 12 are separated from each other atintervals corresponding to ⅔ τp the magnetic pole pitch (correspondingto an electrical angle of 120°) when the number of module armatureblocks is three and the magnetic pole pitch corresponds to an electricalangle of 180°.

In more detail, in the armature block 10, when a terminal of the IN-sideconnector 25 a has phases in sequence of a U phase (Ru), a V phase (Rv),and a W phase (Rw), a terminal of the OUT-side connector 25 b has phasesin sequence of a V phase (Rv), a W phase (Rw), and a U phase (Ru). As aresult of the armature block 11 being coupled to the armature block 10,the terminal of the IN-side connector 25 c has phases in the sequence ofthe V phase (Rv), the W phase (Rw), and the U phase (Ru); and theterminal of the OUT-side connector 25 d has phases in the sequence ofthe W phase (Rw), the U phase (Ru), and the V phase (Rv). Moreover, as aresult of the armature block 12 being coupled to the armature block 11,the terminal of the IN-side connector 25 e has phases in the sequence ofthe W phase (Rw), the U phase (Ru), and the V phase (Rv), and theterminal of the OUT-side connector 25 f has phases in the sequence ofthe U phase (Ru), the V phase (Rv), and the W phase (Rw). Thus, thethree-phase armature windings are coupled together through Y connection.

The first embodiment is embodied by a configuration wherein theconnectors 25 a to 25 f for electrically connecting the lead wires ofthe armature windings 4 coiled around the armature blocks 10, 11, and 12are provided on respective ends of the plurality of the armature blocks10, 11, and 12 such that the connections of the armature windings 4 ofthe respective armature blocks are connected in parallel to each otherand such that the connection between the connectors 25 b and 25 c andthe connection between the connectors 25 d and 25 e, all connectorsbeing provided between the armature blocks, are realized in the form ofin-phase connections, or a configuration wherein the armature blocks areseparated from each other at intervals (⅔ τp) corresponding to theelectrical angle which is an integral multiple of the value determinedby dividing the magnetic pole pitch by the number of sub-divisions ofthe armature blocks. Thrust of the motor is increased to an integralmultiple of the connected armature, and an interlinkage magnetic flux isalso increased to an integral multiple. Thus, an attempt can be made toincrease the thrust when the length of the armature is increased inaccordance with an increase in the stroke of the movable member.

Processing of the lead wires of the armature winding 4 are connectedtogether through use of the connectors 25 a to 25 f without taking thelead wires out of a lower surface of the armature block as is practicedconventionally or taking the lead wires out of the armature mount plateby way of the spacer. Hence, the lead wires do not become bulky on thelower end surface of the armature block. Moreover, molded portions ofthe lead wires can be eliminated by means of resin molding. Therefore,cost reduction and a higher efficiency can be realized at the time ofassembly of the armature block.

The armatures of the linear motor of one type are formed frommodular-type armatures having the same shape and dimensions. Forinstance, the armature is advantageous in that (1) the costs incurred indevelopment of a linear motor to be used in one machine tool can bediminished, and in that (2) even when a failure has arisen in a part ofthe armature block, a necessity for discarding the entire armature orreplacing the armature with a new armature is eliminated, and hence thecosts incurred in performing maintenance of the linear motor can bediminished by requiring only replacement of a part of the block.

SECOND EMBODIMENT

A second embodiment of the present invention will now be described.

FIG. 2 is a plan view of linear motor which shows a second embodiment ofthe invention and describes connection of an armature block andconnection of armature windings.

The second embodiment differs from the first embodiment in that thearmature blocks 10, 11, and 12 are separated from each other atintervals of 4/3 τp the magnetic pole pitch when the magnetic pole pitchof the magnetic field is taken as τp (corresponding to an electricalangle of 180°).

In more detail, in the armature block 10, when the terminal of theIN-side connector 25 a has phases in the sequence of the U phase (Ru),the V phase (Rv), and the W phase (Rw), the terminal of the OUT-sideconnector 25 b has phases in the sequence of the W phase (Rw), the Uphase (Ru), and the V phase (Rv). As a result of the armature block 11being coupled to the armature block 10, the terminal of the IN-sideconnector 25 c has phases in the sequence of the W phase (Rw), the Uphase (Ru), and the V phase (Rv); and the terminal of the OUT-sideconnector 25 d has phases in the sequence of the V phase (Rv), the Wphase (Rw), and the U phase (Ru). Moreover, as a result of the armatureblock 12 being coupled to the armature block 11, the terminal of theIN-side connector 25 e has the phases in the sequence of the V phase(Rv), the W phase (Rw), and the U phase (Ru), and the terminal of theOUT-side connector 25 f has phases in the sequence of the U phase (Ru),the V phase (Rv), and the W phase (Rw). Thus, the three-phase armaturewindings are coupled together through Y connection.

Since the interval between the connectors 25 b and 25 c and the intervalbetween the connectors 25 d and 25 e, all the connectors being providedbetween the respective armature blocks 10, 11, and 12, are set to 4/3τp, the present embodiment yields the same advantage as that yielded bythe first embodiment. The trust can be increased by means of increasingthe stroke of the linear motor by means of selecting a combination ofthe number of magnetic poles of the permanent magnet and the number ofarmature blocks, as appropriate.

THIRD EMBODIMENT

A third embodiment of the present invention will now be described.

FIG. 3 shows a linear motor of a third embodiment of the presentinvention, wherein FIG. 3A is a perspective view of the entire armature,and FIG. 3B is a plan view for describing connection of the armatureblocks.

In FIG. 3, reference numeral 27 designates an engagement projection; 28designates an engagement groove; and 91, 92, and 93 designate armaturemount plates.

The third embodiment differs from the first and second embodiments inthat the armature mount plates 91, 92, and 93 for retaining the armatureblocks are provided in the respective armature blocks 10, 11, and 12 inthe direction of thrust of the linear motor 1; in that the engagementprojection 27 is provided at one end of each of the armature mountplates 91 to 93, and the engagement groove 28 is formed in the other endof each of the same; and in that the armature blocks are joinedtogether.

In the third embodiment, the armature mount plates 91 to 93 provided foreach of the armature blocks 10, 11, and 12 are coupled together by meansof the engagement projections 27 and the engagement grooves 28. Thepresent embodiment can contribute to an operation for assembling thearmature blocks as well as an increase in the efficiency of assembly ofthe entire armature.

The present embodiment shows an example in which connectors to be usedfor electrically connecting the lead wires of the armature windings areprovided on both ends of the armature blocks such that connections ofthe respective armature blocks and connections of the armature windingsbecome parallel. However, a configuration in which the connections ofthe armature windings are made in series may also be adopted. In such acase, there is yielded the same advantage as that yielded in the case ofthe parallel connections.

The explanations are provided for the embodiment, wherein the engagementprojection is provided at one end of the armature mount plate providedin each armature block, and the engagement groove is formed in the otherend of the same, thereby coupling the armatures together. However,pin-shaped projections, and grooves to be engaged with the projectionsmay be provided in place of the engagement projections and grooves.

INDUSTRIAL APPLICABILITY

As mentioned above, the linear motor of the present invention isutilized for, e.g., applications of precision feeding of a machine toolor a semiconductor manufacturing apparatus and is useful as an armatureof a linear motor suitable for a longer stroke of the movable elementand as a linear motor.

1. An armature of a linear motor comprising: a modular-type armaturewhich is divided into a plurality of armature blocks and around which anarmature winding is coiled, a plurality of the armature blocks beingformed by sequentially coupling a plurality of block cores, andconnectors to be used for electrically connecting lead wires of armaturewindings coiled around the armature blocks provided on both ends of aplurality of the armature blocks so that connections of the respectivearmature blocks and connections of the armature windings become serialor parallel, wherein the connectors provided between the armature blocksare connected in a form of in-phase connections wherein if an in-sideconnector of one of said armature blocks has terminals in a sequence ofphases u, v and w, an out-side connector of said one of said armatureblocks has terminals in a sequence of phase of v, w, and u.
 2. Thearmature of a linear motor according to claim 1, wherein when the numberof the armature windings is three and a magnetic pole pitch of amagnetic field is taken as τp, the armature blocks are separated fromeach other at intervals corresponding to an electrical angle of anintegral multiple determined by dividing the magnetic pole pitch by anumber of sub-divisions of the armature blocks.
 3. The armature of alinear motor according to claim 2, wherein the armature blocks areseparated from each other at intervals of ⅔ the magnetic pole pitch. 4.The armature of a linear motor according to claim 2, wherein thearmature blocks are separated from each other at intervals of 4/3 themagnetic pole pitch.
 5. The armature of a linear motor according to anyone of claims 1 through 4, further comprising: an armature mount platewhich is arranged in the direction of thrust of the linear motor andprovides a retaining function provided on each of the armature blocks,and an engagement projection provided at one end of each armature mountplate, wherein an engagement groove is formed in the other end of thesame to couple together the armature blocks.
 6. A linear motorcomprising: an armature of the linear motor defined in claim 1, and amagnetic field disposed so as to oppose the armature by way of a gap,wherein the magnetic field is generated by a yoke having a plurality ofpermanent magnets disposed therein such that different polarities arearranged alternately, and either the armature or the magnetic field istaken as a movable element which moves, and the other is taken as astator.